Depreciation of Fluorescent Lamps without Passage of Current

摘要

Fluorescent lamps with thin and with partial coatings of phosphor on bulbs of ultraviolet transmitting glass were irradiated with Hg 2537 radiation. Comparison with similar lamps which were burned showed a decline in lumen output which was of the same general character in all experiments, except for different time factors. This indicates that the process of lamp depreciation is fundamentally of photochemical nature, involving excited mercury, but not requiring either Hg ions or neutral atoms. It is assumed that superficial oxygen ions of the phosphor crystal react with Hg* to form links of the type‐SiO‐O‐Hg‐Hg..., thus tying mercury to the crystal with a resulting loss of phosphor brightness.